SRP A Multimedia Protocol Ken French George Oprica Mike Piecuch - PDF document

SRP A Multimedia Protocol Ken French George Oprica Mike Piecuch Advisor: Mark Claypool 5/15/00 1 Multimedia Characteristics Loss Latency 5/15/00 2 SRP - A Multimedia Protocol 1

Multimedia Over TCP Guaranteed delivery (No loss) Flow Control Unbounded delay 5/15/00 3 Multimedia Over UDP Best effort delivery (minimal latency) Unbounded loss 5/15/00 4 SRP - A Multimedia Protocol 2

Multimedia Over SRP Selective Retransmission Protocol Combination of TCP & UDP Retransmits a percentage of lost packets Application layer client/server protocol 5/15/00 5 SRP Implementation Algorithms Equal Loss Latency (ELL) Optimum Quality (OQ) 5/15/00 6 SRP - A Multimedia Protocol 3

Testing Approach UDP blaster Token bucket router 5/15/00 7 Sample Data SRP - ELL (3% loss, 50ms) 250 45 40 200 35 30 Lost Packets Latency (ms) 150 25 20 100 15 10 50 5 0 0 1 51 101 151 201 251 301 351 401 451 501 551 601 Packet Number 5/15/00 8 SRP - A Multimedia Protocol 4

Low Loss, Low Latency 3% Loss , 50 ms Round Trip Time 1.4 1.2 Latency (normalized) 1 SRP - ELL 0.8 SRP - OQ UDP 0.6 TCP 0.4 0.2 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 Loss (normalized) 5/15/00 9 High Loss, High Latency 15% Loss , 275 ms Round Trip Time 2 1.8 1.6 1.4 Latency (normalized) 1.2 SRP - ELL 1 SRP - OQ UDP 0.8 0.6 0.4 0.2 0 0 0.5 1 1.5 2 Loss (normalized) 5/15/00 10 SRP - A Multimedia Protocol 5

Conclusions SRP is a good balance Great potential Additional tuning 5/15/00 11 Future Work Flow control Loss detection Additional algorithms 5/15/00 12 SRP - A Multimedia Protocol 6